Types of Fire Extinguishers

A fire extinguisher is a hand-held, portable device that can be used to stop or control a small fire before it becomes a major catastrophe. Extinguishers are available in a variety of sizes and types. The most common types are ABC, dry chemical, and Halon (classes B and C). Each type has a specific use.

The fire extinguisher industry is changing rapidly. Many companies now offer electronic monitoring for extinguishers. These systems monitor a fire extinguisher’s physical presence, internal pressure, and whether an obstruction exists that would prevent ready access. The system can also send an alert when it is time to refill the extinguisher. Some systems even keep a log that can be downloaded for record keeping purposes.

Some types of fire extinguishers are now available that do not require maintenance or a trained technician. These devices are known as rechargeable fire extinguishers. A rechargeable fire extinguisher has a metal valve and is filled with a proprietary mixture that is mixed at the factory when the unit is sold, or it can be easily refilled with standard chemicals such as baking soda and salt.

In the United States these units are typically found in public buildings and some offices. They come in various sizes from 5 to 20 pounds of monoammonium phosphate. Monoammonium phosphate is a finely ground extinguishing agent that looks like yellow talcum powder. Nitrogen gas is used as a propellant. They are effective on class A, B, and C fires. They are easy to operate. Simply pull the pin, aim at the base of the fire and sweep from side to side. They have a range of about 15 feet.

These are similar to the dry powder extinguishers but they contain liquid carbon dioxide (CO2). They are designed to put out a small fire of flammable liquids such as gasoline, oil and paint. These fires can be very dangerous as the vapor and combustion by-products can be toxic. They are also difficult to extinguish as the liquid CO2 cools the fire and it dries out quickly.